SD cards use SPI (pins 11/12/13) not I2C. Is your problem related to the SD card, or related to some other device that actually uses I2C? If you're using I2C, have you called Wire.begin() ?
SD cards use SPI (pins 11/12/13) not I2C. Is your problem related to the SD card, or related to some other device that actually uses I2C? If you're using I2C, have you called Wire.begin() ?